Dispensing nozzle tip

ABSTRACT

An upper end  3  of a nozzle tip  2  is adapted to have an inside diameter dimension smaller than an outside diameter of a lower portion of a barrel  4 , so that nozzle tips  2  are not piled up. An upper curved surface  11 , which is curved in an outer direction of the nozzle tip  2  starting with a boundary portion between the barrel  4  and a leading end opening  5  of the nozzle tip  2  and the leading end opening  5 , is formed. A lower curved surface  12  is formed continuously from the upper curved surface  11  to be curved in an inner direction. An angle formed between a line tangent to a boundary portion  13  between the upper curved surface  11  and the lower curved surface  12  and a center axis of the nozzle tip  2  is adapted to fall within a range between 45° and 20°.

INCORPORATION BY REFERENCE

The present application claims priority from Japanese applicationJP2007-072868 filed Mar. 20, 2007, the content of which is herebyincorporated by reference into this application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a dispensing nozzle tip for a samplesuch as blood or urine, or a liquid such as water or reagent.

2. Description of the Related Art

The dispensing nozzle tip is connected to a dispensing apparatus andused for aspirating and discharging a liquid. The dispensing nozzle tiptypically includes a barrel of a cylindrical shape and a lower leadingend of a conical trapezoidal shape with a tapered end.

Because of its very shape, nozzle tips tend to pile up, which hampersautomatic loading of the nozzle tip. To prevent this, a knownarrangement, as disclosed in JP-A-2003-38966, includes a stopper adaptedto have an outside diameter larger than an inside diameter of anopening.

SUMMARY OF THE INVENTION

There is a need the art for enhanced analysis accuracy in analyzingblood, urine, or other samples. This leads to a need for aspiration anddischarge of an accurate amount of a liquid sample or reagent.

As described above, the lower leading end of the dispensing nozzle tiphas a tapered conical trapezoidal shape. As a result, liquid turbulencecaused by channel resistance tends to occur. This is considered tohamper aspiration and discharge of an accurate amount of the liquidsample or the like.

The known art prevents the dispensing nozzle tips from being piled up.No known art has, however, examined the channel resistance at the lowerleading end of the nozzle tip.

It is an object of the present invention to achieve a dispensing nozzletip that prevents dispensing nozzle tips from being piled up andenhances dispensing as well as control accuracy by reducing channelresistance of a liquid in aspiration and discharge of the liquid.

A dispensing nozzle tip according to an aspect of the present inventioncomprises an upper end, a barrel, and a leading end. Specifically, theupper end has an opening into which the dispensing apparatus isinserted. The barrel is connected to the upper end and accommodatestherein a liquid sample or a liquid reagent. The leading end isconnected to the barrel and has an opening through which the liquidsample or the liquid reagent is aspirated or discharged. Further, theupper end has an inside diameter smaller than an outside diameter of thebarrel. The leading end has an inner surface formed thereon. The innersurface includes an upper curved surface and a lower curved surface. Theupper curved surface is curved in an outer direction of the dispensingnozzle tip starting with a boundary portion relative to the barrel. Thelower curved surface is formed continuously from the upper curvedsurface to be curved in an inner direction of the dispensing nozzle tip.

In the dispensing nozzle tip according to another aspect of the presentinvention, the upper end has an inside diameter smaller than an outsidediameter of the barrel. Further, the leading end has an inner surfaceincluding a plurality of deflecting ridges formed thereon. Thedeflecting ridges extend from at least a boundary portion relative tothe barrel toward the opening through which the liquid sample or theliquid reagent is aspirated or discharged.

In the dispensing nozzle tip according to still another aspect of thepresent invention, the upper end has a scrap escape and a fittingportion. The scrap escape has an inside diameter larger than an outsidediameter of the dispensing apparatus. The fitting portion has an insidediameter smaller than the inside diameter of the scrap escape andfixedly receives the dispensing apparatus inserted thereinto. Further,the upper end has an inside diameter smaller than an outside diameter ofthe barrel.

The dispensing nozzle tip according to the aspects of the presentinvention has the following effects. Specifically, the dispensing nozzletips can be prevented from being piled up. Channel resistance of aliquid in aspiration and discharge of the liquid can be reduced, so thatdispensing as well as control accuracy is enhanced.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a view showing a condition, in which a nozzle tip according toan embodiment of the present invention is loaded in a nozzle tip mount.

FIG. 2 is a cross-sectional view showing the nozzle tip according to theembodiment of the present invention.

FIG. 3 is a cross-sectional view showing an upper end of the nozzle tipaccording to the embodiment of the present invention.

FIG. 4 is a conceptual view showing internal shapes at a boundaryportion between a lower portion of a barrel and a leading end opening ofthe nozzle tip according to the embodiment of the present invention.

FIG. 5 is a cross-sectional view showing the lower portion of the barreland the leading end opening of the nozzle tip according to theembodiment of the present invention.

FIG. 6 is a cross-sectional view showing the internal construction ofthe barrel and the leading end opening.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A preferred embodiment of the present invention will be described belowwith reference to the accompanying drawings.

FIG. 1 is a view showing a condition, in which a nozzle tip 2 accordingto the embodiment of the present invention is loaded in a dispensingapparatus nozzle tip mount 1 and a liquid 2-1 is aspirated. FIG. 2 is across-sectional view showing the nozzle tip 2 according to theembodiment of the present invention. FIG. 3 is a cross-sectional viewshowing an upper end of the nozzle tip 2 according to the embodiment ofthe present invention.

Referring to FIG. 1, the nozzle tip 2 according to the embodiment of thepresent invention includes an upper end 3, a barrel 4, and a leading endopening 5. The dispensing apparatus nozzle tip mount 1 is inserted andfixed in the upper end 3. The barrel 4 aspirates and holds the liquid2-1. The leading end opening 5 aspirates and discharges the liquid 2-1.

Referring to FIG. 3, the upper end 3 includes a scrap escape 6 formedtherein, relative to insertion of the dispensing apparatus nozzle tipmount 1 into the nozzle tip 2.

A plastic scrap 9 produced during injection molding of the nozzle tip 2very often attaches to a location near a material injection port 8 usedduring injection molding.

Accordingly, if the plastic scrap 9 is shaved by the dispensingapparatus nozzle tip mount 1 as the nozzle tip mount 1 is inserted intothe upper end 3, the plastic scrap 9 is wedged between the nozzle tipmount 1 and an inner surface of the nozzle tip 2 at a fitting portion 7.This not only impairs airtightness of an inside of the nozzle tip 2, butalso reduces fixation performance of the nozzle tip mount 1 in thenozzle tip 2.

The scrap escape 6 is intended to achieve proper airtightness andfixation performance. The scrap escape 6 typically has an insidediameter larger by, for example, 0.2 mm than an outside diameter of thenozzle tip mount 1. This arrangement prevents the nozzle tip mount 1from moving the plastic scrap 9 onto the fitting portion 7. The scrapescape 6 prevents fitting performance between the nozzle tip mount 1 andthe nozzle tip 2 from being degraded, achieving good airtightness duringaspiration and discharge.

FIG. 4 is a conceptual view showing internal shapes at a boundaryportion between a lower portion of the barrel 4 and the leading endopening 5 of the nozzle tip 2 according to the embodiment of the presentinvention.

Referring to FIG. 4, an upper curved surface 11 is formed over an areafrom the boundary portion between the barrel 4 and the leading endopening 5 of the nozzle tip 2 and the leading end opening 5. The uppercurved surface 11 has an outward curvature relative to the nozzle tip 2.The upper curved surface 11 continues into a lower curved surface 12that has an inward curvature relative to the nozzle tip 2. A linetangent to a boundary portion 13 (a point at which the outward curvaturechanges to the inward curvature) between the upper curved surface 11 andthe lower curved surface 12 extends at an angle of 45° to 20° relativeto a center axis of the nozzle tip 2.

An extension from an end point of the lower curved surface 12 isstraight toward the leading end.

As such, the leading end opening 5 has an inner surface that includes astepless curved surface and a straight surface. This prevents turbulencefrom occurring in a liquid stream in aspiration and discharge of theliquid 2-1 shown in FIG. 1, thereby enhancing dispensing accuracy.

If the angle formed between the line tangent to the boundary portion 13and the center axis of the nozzle tip 2 is about 45° as shown in FIG. 4with an overall length of the nozzle tip 2 and a length and an insidediameter of the leading end opening 5 defined, the barrel 4 can have amaximum possible length, achieving a maximum possible amount of liquidto be aspirated.

A quadratic curve of an arc or the like, an exponent function, astreamline shape, or the like is applicable to the shape of the curvedsurfaces 11, 12.

The volume of the liquid 2-1 shown in FIG. 1 can be measured bymeasuring the height of the liquid level from the outside, if the barrel4 of the nozzle tip 2 shown in FIG. 1 is adapted to have an insidediameter dimension that is as identical as possible throughout (byminimizing inclination).

Further, the upper end 3 of the nozzle tip 2 shown in FIG. 1 has aninside diameter dimension smaller than an outside diameter of a lowerportion of the barrel 4 of the nozzle tip 2. This prevents the nozzletip 2 from being piled up.

FIG. 5 is a cross-sectional view showing the lower portion of the barrel4 and the leading end opening 5 of the nozzle tip 2. FIG. 6 is across-sectional view showing the internal construction of the barrel 4and the leading end opening 5.

Referring to FIG. 5, a deflecting ridge 15 is formed on an inner surfaceof the nozzle tip 2 shown in FIG. 1. This arrangement allows turbulenceof the liquid stream during aspiration and discharge of the liquid 2-1shown in FIG. 1 to be further prevented.

The deflecting ridge 15 is formed on an area ranging from the end of thebarrel 4 to a location near an opening end of the leading end opening 5.In the example shown in FIG. 6, four deflecting ridges 15 are formed,each being equally spaced apart from each other. Each of these fourdeflecting ridges 15 does not contact each other on the center axis ofthe nozzle tip 2.

Referring to FIG. 6, a thickness 17 of a curved surface joint (a jointbetween the barrel 4 and the leading end opening 5), a thickness 18 ofthe deflecting ridge 15 formed in number at least 3, and a thickness 20of a dispensing opening (the straight portion in the leading end opening5) and the deflecting ridges 15 are adjusted, so that an openingdiameter at an identical diameter opening portion 21 of FIG. 6 isapproximated to a leading end inside diameter 19 of the leading endopening 5 of the nozzle tip 2 shown in FIG. 1. This allows micro foreignmatter mixed with the liquid, which is not currently detectable, to bedetected.

Specifically, forming the deflecting ridge 15 allows foreign mattertrapped in the nozzle tip 2 to be retained by the deflecting ridge 15.This causes an aspiration pressure to fluctuate, which allows trap ofthe foreign matter to be detected.

Preferably, the deflecting ridge 15 in the identical diameter openingportion 21 should have a total cross-sectional area of 30% or more of across-sectional inside diameter area of the nozzle tip 2. As long asthis requirement is satisfied, the deflecting ridge 15 is not limited innumber to 4.

The height of deflecting ridge 15 can be assumed more than the diameterof φ0<φa1<φa2 shown in FIG. 6 leading end opening 5.

As described heretofore, the dispensing nozzle tip 2 according to theembodiment of the present invention is constructed so as to prevent thedispensing nozzle tip 2 from being piled up through the arrangement, inwhich the upper end 3 has an inside diameter dimension smaller than theoutside diameter dimension of the lower portion of the barrel 4 of thenozzle tip 2. Further, the barrel 4 and the leading end opening 5 arejoined together through a curved surface, so that no turbulence occursin the liquid stream that would otherwise occur during aspiration anddischarge of the liquid. The nozzle tip 2 according to the embodiment ofthe present invention can thereby stabilize the liquid stream.

The upper end 3, into which the dispensing apparatus nozzle tip mount 1is inserted, includes the scrap escape 6 formed thereon. This helpsprevent adhesion properties from being degraded, as caused by scrap leftin a gate during manufacturing of the nozzle tip.

In addition, during the manufacture of the nozzle tip, the barrel 4 ismade to have an inside diameter dimension resulting in a cylindricalshape as much as possible. This allows the volume of the liquidcontained in the nozzle tip to be detected by detecting the level of theliquid from the outside.

Further, the arrangement, in which the deflecting ridge 15 is formed onthe inside of the leading end opening 5, helps suppress turbulence inthe liquid stream. The deflecting ridge 15 is also adapted to have aninside diameter equal to the dimension of the dispensing opening. Thisallows foreign matter trapped in the liquid to be detected as cloggedaspiration.

1. A dispensing nozzle tip for dispensing a liquid sample or a liquidreagent by means of a dispensing apparatus, the dispensing nozzle tipcomprising: an upper end portion having an opening into which thedispensing apparatus is inserted; a barrel portion connected to theupper end portion, the barrel portion accommodating therein the liquidsample or the liquid reagent; a leading end portion connected to thebarrel portion, the leading end portion having an opening through whichthe liquid sample or the liquid reagent is aspirated or discharged; anda connection portion connecting the leading end portion and the barrelportion; wherein the upper end portion has an inside diameter smallerthan an outside diameter of the barrel portion; wherein an inner surfaceof the connection portion consists of an upper curved surface and alower curved surface that are smoothly and continuously directlyconnected to each other, wherein the upper curved surface extends in anoutwardly curved surface relative to the nozzle tip from the barrelportion to an inner side of the dispensing nozzle tip; wherein the lowercurved surface extends in an inwardly curved surface relative to thenozzle tip from the upper curved surface to the leading end portion andis smoothly and continuously connected with the leading end portion; andwherein an angle formed between a line tangent to a boundary portionbetween the upper curved surface and the lower curved surface of theleading end portion and a center axial axis of the dispensing nozzle tipis 45° or less.
 2. The dispensing nozzle tip according to claim 1,wherein the upper end portion has an inside diameter smaller than anoutside diameter of the barrel portion; and wherein the leading endportion has an inner surface including a plurality of deflecting ridgesformed thereon, the deflecting ridges extending from at least a boundaryportion relative to the barrel portion toward the opening through whichthe liquid sample or the liquid reagent is aspirated or discharged. 3.The dispensing nozzle tip according to claim 1, wherein the upper endportion has a scrap escape having an inside diameter larger than anoutside diameter of the dispensing apparatus and a fitting portionhaving an inside diameter smaller than the inside diameter of the scrapescape and fixedly receiving the dispensing apparatus inserted therein.4. The dispensing nozzle tip according to claim 3, wherein the leadingend portion has an inner surface formed thereon, including an uppercurved surface and a lower curved surface, the upper curved surfacebeing curved in an outer direction of the dispensing nozzle tip startingwith a boundary portion relative to the barrel portion and the lowercurved surface being formed continuously from the upper curved surfaceto be curved in an inner direction of the dispensing nozzle tip; andwherein the leading end portion has an inner surface including aplurality of deflecting ridges formed thereon, the deflecting ridgesextending from at least a boundary portion relative to the barrelportion toward the opening through which the liquid sample or the liquidreagent is aspirated or discharged.
 5. The dispensing nozzle tipaccording to claim 1, wherein the upper curved surface and the lowercurved surface of the leading end portion are formed according to anexponential function curve; and wherein an angle formed between a linetangent to a boundary portion between the upper curved surface and thelower curved surface of the leading end portion and a center axial axisof the dispensing nozzle tip falls within a range between 45° and 20°.6. The dispensing nozzle tip according to claim 1, wherein the barrelportion is substantially a cylindrical shape.
 7. The dispensing nozzletip according to claim 2, wherein the deflecting ridges have a heightmore than a diameter of the opening of the leading end portion.